A mixed mineral material and method for promoting long-term sequestration of sediment organic carbon

Abstract

The application discloses a kind of mixed mineral materials and methods for promoting long-term storage of sediment organic carbon, the material is composed of a certain proportion of serpentine and magnesite, steps are: 1) select mineral material serpentine and magnesite as raw material;2) serpentine and magnesite are pretreated;3) the serpentine and magnesite after pretreatment are mixed according to certain proportion;4) the mixed mineral material is spread to sediment surface with certain thickness;5) through the reaction of mixed mineral material and sediment organic carbon to generate stable magnesium carbonate mineral, realize long-term storage of sediment organic carbon in situ.The mineral material in the application has the characteristics of environmental friendly, reasonable formula, convenient to use, ecological environmental protection and the like.The application realizes long-term storage of sediment organic carbon in situ by the reaction of mixed mineral material and organic carbon, provides new ideas for water ecological restoration engineering to help carbon neutralization and realize sediment in situ carbon storage.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of water ecological restoration and carbon emission reduction, and more particularly relates to a mixed mineral material, and also relates to a method for promoting long-term storage of sediment organic carbon, which can be applied to ecological restoration engineering of polluted water bodies. BACKGROUND

[0002] Water ecosystems are a global source of important greenhouse gases, and the continuous eutrophication of global freshwater ecosystems will lead to an increase in greenhouse gas emissions from lakes. The carbon cycle intensity of lakes is generally higher than that of grasslands, forests and other land units, and plays an important role in global carbon cycle. Global lakes emit about 110-570 billion tons of CO2 to the atmosphere every year, which is a typical carbon source.

[0003] Sediments are the main place for the mineralization of organic matter, and lake sediments are important carbon accumulation sites and important nutrient sources and activity sites of lake ecosystems. The state of sediments significantly affects the production and emission of greenhouse gases in lakes. Since 1850, the nutrient level of Chinese lakes has increased rapidly, and the average concentrations of nitrogen and phosphorus in sediments have increased by 267% and 202%, respectively. The release of endogenous pollution will lead to an increase in the levels of nutrients such as nitrogen and phosphorus in inland water bodies, thereby causing water eutrophication and water quality deterioration, and is expected to further exacerbate the emission of greenhouse gases in water bodies. Greenhouse gases in aquatic ecosystems are mainly emitted to the atmosphere through the sediment-water-atmosphere system. Dissolved organic matter in sediments is one of the largest active carbon pools on earth, and the fate of organic matter in sediments plays a crucial role in the production of greenhouse gases. How to effectively and long-term store organic carbon in sediments has become a major problem faced by China in water ecological governance and restoration under the "double carbon" goal.

[0004] Currently, existing research and successful cases of promoting the storage of organic carbon in sediments show that organic carbon combined with active iron oxides can fix carbon to some extent, but it is unstable and microbial activity can accelerate its decomposition. The main technical difficulty is that it is difficult to effectively and stably store organic carbon in sediments. SUMMARY

[0005] The purpose of the present application is to solve the technical problem of how to effectively and long-term store organic carbon in sediments, and a mixed mineral material for promoting long-term storage of sediment organic carbon is provided. The mineral material in the present application is environmentally friendly, has a reasonable formula, is easy to use, is eco-friendly, and has a significant effect.

[0006] Another object of the present application is to provide a method for promoting long-term storage of sediment organic carbon, which is easy to operate and has significant environmental benefits.

[0007] In order to achieve the above-mentioned object, the present application adopts the following technical solutions:

[0008] The present application aims to achieve long-term storage of sediment organic carbon in situ by mixing mineral materials with organic carbon, providing a new idea for water ecological restoration projects to help carbon neutralization and achieve in-situ carbon storage of sediments.

[0009] A mixed mineral material for promoting long-term storage of sediment organic carbon is made from the following mass fraction of raw materials:

[0010] Raw materials %

[0011] Serpentine 70-90

[0012] Magnesite 10-30.

[0013] A mixed mineral material for promoting long-term storage of sediment organic carbon is made from the following mass fraction of raw materials (preferred range):

[0014] Raw materials %

[0015] Serpentine 75-90

[0016] Magnesite 10-25.

[0017] A mixed mineral material for promoting long-term storage of sediment organic carbon is made from the following mass fraction of raw materials (preferred range):

[0018] Raw materials %

[0019] Serpentine 78-85

[0020] Magnesite 15-22.

[0021] A mixed mineral material for promoting long-term storage of sediment organic carbon is made from the following mass fraction of raw materials (preferred range):

[0022] Raw materials %

[0023] Serpentine 79-82

[0024] Magnesite 18-21.

[0025] A mixed mineral material for promoting long-term storage of sediment organic carbon is made from the following mass fraction of raw materials (best value):

[0026] Raw material %

[0027] Serpentine 80

[0028] Magnesite 20.

[0029] Serpentine is a water-rich magnesium silicate mineral, the main component is magnesium oxide and silicon dioxide. Mohs hardness is between 2.5 to 4, from igneous rock. Serpentine minerals have wide application prospects due to their heat resistance, corrosion resistance, wear resistance, heat and sound insulation, good process characteristics and associated beneficial components. China is rich in serpentine resources with good quality. The main mineral resources are Shanzuokou in Donghai County of Jiangsu Province, Zhangshudun in Yiyang County of Jiangxi Province, Wohu in Xinyang County of Henan Province, Heimulin in Ningqiang County of Shaanxi Province, Jianchaling in Lueyang County and Anzishan in Mianxian County.

[0030] Magnesite is a carbonate mineral of the trigonal system, usually in the form of crystalline or cryptocrystalline dense block, the composition of magnesite mainly has magnesium carbonate, often has iron and manganese instead of magnesium, Mohs hardness 3.5-4.5, specific gravity 2.9-3.1. It is mainly used for refractory materials, building materials, chemical raw materials and extraction of magnesium and magnesium compounds.

[0031] The applicant has carried out related research on improving the substrate microecology and controlling endogenous pollution of mineral materials, but there is no related report on promoting the long-term storage of sediment organic carbon by mineral materials. Through a large number of research and experimental demonstration, the present application first mixes the above two materials in a certain proportion to prepare a mixed mineral material, which is applied to promote the storage of lake sediment organic carbon and repair engineering.

[0032] Among the two materials, the most critical is serpentine, which is a water-rich magnesium silicate mineral that can fix CO2 and dissolved organic carbon into stable carbonate minerals through a thermodynamically favorable alteration process.

[0033] The proportion of the two materials of serpentine and magnesite is the most suitable proportion obtained through a large number of experimental research and engineering application. Magnesite is a carbonate mineral containing magnesium, with a trigonal system, single crystal in rhombohedron, and aggregate in crystalline or cryptocrystalline dense block. Therefore, the present application combines the above two materials in a certain proportion to fully exert the characteristics and advantages of the two materials, and prepares a mixed mineral material. Through the reaction of the mixed mineral material with organic carbon, the long-term storage of sediment organic carbon in situ is realized, which provides a new idea for water ecological repair engineering, carbon neutralization and sediment in-situ carbon storage.

[0034] A method for promoting long-term storage of sediment organic carbon, the steps are:

[0035] 1) A certain proportion of serpentine is soaked in dilute hydrochloric acid with a mass fraction of 2-5% for 1-2h, then washed to neutral with water, and standby;

[0036] 2) A certain proportion of magnesite is soaked in dilute hydrochloric acid with a mass fraction of 1-2% for 1-2 hours, and then washed with clean water until neutral, ready for use;

[0037] 3) The pretreated serpentine and magnesite are mixed uniformly according to a certain mass fraction to prepare a mixed mineral material;

[0038] 4) The mixed mineral material is spread on the surface of the sediment to a certain thickness (1-2 cm);

[0039] 5) The organic carbon in the sediment is reacted with the mixed mineral material to realize long-term in-situ storage of the organic carbon in the sediment.

[0040] Through the above technical measures: the most critical is to mix the pretreated serpentine and magnesite uniformly according to a certain mass fraction to prepare a mixed mineral material, which mainly solves the technical difficulty of long-term effective storage of organic carbon in the sediment, and provides a new idea for water ecological restoration project to help carbon neutralization and realize in-situ carbon storage of the sediment. Through the whole technical measure, more than 60% of the organic carbon in the surface layer (0-10 cm) of the sediment is converted into stable magnesium carbonate minerals. The research team of the applicant has previously studied that silicate minerals and submerged plants can reduce greenhouse gas emissions to a certain extent, but cannot effectively store carbon. The invention has the following advantages and effects compared with the prior art: the mixed mineral material is prepared by mixing serpentine and magnesite, which can effectively and long-term store the organic carbon in the sediment, and effectively solves the major technical problem faced by China's water ecological management and restoration under the "double carbon" target.

[0041] Compared with the prior art, the present application has the following advantages and effects:

[0042] 1. The method is easy and simple to operate, and has significant environmental and social benefits;

[0043] 2. The mixed mineral material is composed of natural minerals, is eco-friendly, and has no secondary pollution;

[0044] 3. The natural material characteristics are fully utilized, which can significantly promote long-term effective storage of organic carbon in the sediment, and compared with the control group, more than 60% of the organic carbon in the surface layer (0-10 cm) of the sediment is converted into stable magnesium carbonate minerals after 2 months. DETAILED DESCRIPTION

[0045] In order to better understand the present application, the content of the present application will be further illustrated below in combination with examples, but the content of the present application is not limited to the following examples.

[0046] Example 1:

[0047] A mixed mineral material for promoting long-term storage of organic carbon in the sediment, which is made of the following mass fraction of raw materials:

[0048] Raw materials %

[0049] serpentine 71

[0050] magnesite 29.

[0051] A method for promoting long-term storage of sediment organic carbon, the steps are:

[0052] 1) a certain proportion of serpentine is placed in dilute hydrochloric acid with a mass fraction of 2% for 1h, then washed with clean water to neutral, ready for use;

[0053] 2) a certain proportion of magnesite is placed in dilute hydrochloric acid with a mass fraction of 1% for 1h, then washed with clean water to neutral, ready for use;

[0054] 3) the pretreated serpentine and magnesite are mixed uniformly according to the above mass fraction to prepare a mixed mineral material;

[0055] 4) the mixed mineral material is spread on the surface of the sediment, with a thickness of 1cm;

[0056] 5) through the reaction of the mixed mineral material and sediment organic carbon, the in-situ long-term storage of sediment organic carbon is realized.

[0057] After a period of implementation, the proportion of sediment surface layer (0-10cm) organic carbon converted into stable carbon (%) is shown in Table 1, in which Example 1 organic carbon is converted into stable magnesium carbonate mineral.

[0058] Table 1 proportion of organic carbon converted into stable carbon in Example 1

[0059]

[0060] Example 2:

[0061] A mixed mineral material for promoting long-term storage of sediment organic carbon, which is made of the following mass fraction of raw materials:

[0062] Raw materials %

[0063] serpentine 80

[0064] magnesite 20.

[0065] A method for promoting long-term storage of sediment organic carbon, the steps are:

[0066] 1) a certain proportion of serpentine is placed in dilute hydrochloric acid with a mass fraction of 5% for 2h, then washed with clean water to neutral, ready for use;

[0067] 2) a certain proportion of magnesite is placed in dilute hydrochloric acid with a mass fraction of 2% for 2h, then washed with clean water to neutral, ready for use;

[0068] 3) The pre-treated serpentine and magnesite are mixed in the above mass ratio to form a mixed mineral material;

[0069] 4) The mixed mineral material is spread on the sediment surface with a thickness of 2 cm;

[0070] 5) The organic carbon in the sediment is reacted with the mixed mineral material to achieve long-term in-situ storage of the organic carbon in the sediment;

[0071] After a period of implementation, the percentage of the organic carbon in the surface layer (0-10 cm) of the sediment that is converted into stable carbon is shown in Table 2, where the organic carbon in Example 2 is converted into stable magnesium carbonate minerals.

[0072] Table 2 Percentage of organic carbon converted into stable carbon in Example 2

[0073]

[0074]

[0075] Example 3:

[0076] A mixed mineral material for promoting long-term storage of organic carbon in sediments is made from the following raw materials in the following mass percentages:

[0077] Raw material %

[0078] Serpentine 89

[0079] Magnesite 11

[0080] The preparation steps are the same as in Example 1.

[0081] After a period of implementation, the percentage of the organic carbon in the surface layer (0-10 cm) of the sediment that is converted into stable carbon is shown in Table 3, where the organic carbon in Example 3 is converted into stable magnesium carbonate minerals.

[0082] Table 3 Percentage of organic carbon converted into stable carbon in Example 3

[0083]

[0084] Example 4:

[0085] A mixed mineral material for promoting long-term storage of organic carbon in sediments is made from the following raw materials in the following mass percentages:

[0086] Raw material %

[0087] Serpentine 85

[0088] Magnesite 15

[0089] The preparation steps are the same as in Example 2.

[0090] After a period of implementation, the percentage (%) of organic carbon converted into stable carbon in the surface layer (0-10 cm) of sediments is shown in Table 4, where in Example 4, organic carbon was converted into stable magnesium carbonate minerals.

[0091] Table 4. Proportion of Organic Carbon Converted to Stable Carbon in Example 4

[0092]

[0093] Example 5

[0094] A mixed mineral material that promotes long-term sequestration of organic carbon in sediments, made from the following raw materials by mass fraction:

[0095] raw material%

[0096] Serpentine 82

[0097] Magnesite 18

[0098] The preparation steps are the same as in Example 1 or 2.

[0099] After a period of implementation, the percentage (%) of organic carbon converted into stable carbon in the surface layer (0-10 cm) of sediments is shown in Table 5, where in Example 5, organic carbon was converted into stable magnesium carbonate minerals.

[0100] Table 5. Proportion of Organic Carbon Converted to Stable Carbon in Example 5

[0101]

[0102] For the first time, it has been discovered that mixing serpentine and magnesite to prepare a mixed mineral material can efficiently and long-term preserve organic carbon in sediments, effectively solving a major technical challenge faced by China in water ecological governance and restoration under the "dual carbon" target.

Claims

1. A method for promoting long-term sequestration of organic carbon in sediments, characterized in that, The steps are as follows: 1) Soak a certain proportion of serpentine in dilute hydrochloric acid with a mass fraction of 2-5% for 1-2 hours, then rinse with water until neutral, and set aside. 2) Soak a certain proportion of magnesite in 1-2% dilute hydrochloric acid for 1-2 hours, then wash with water until neutral, and set aside. 3) Mix the pretreated serpentine and magnesite evenly according to a certain mass fraction to prepare a mixed mineral material; 4) Spread the mixed mineral material to a certain thickness on the surface of the sediment; 5) Long-term in-situ preservation of organic carbon in sediments is achieved through the reaction of mixed mineral materials and sediment organic carbon; The method uses a mixed mineral material made from the following raw materials by mass fraction: raw material% Serpentine 70-90 Magnesite 10-30.

2. The method for promoting long-term sequestration of organic carbon in sediments according to claim 1, characterized in that: raw material% Serpentine 75-90 Magnesite 10-25.

3. The method for promoting long-term sequestration of organic carbon in sediments according to claim 1, characterized in that: raw material% Serpentine 78-85 Magnesite 15-22.

4. The method for promoting long-term sequestration of organic carbon in sediments according to claim 1, characterized in that: raw material% Serpentine 79-82 Magnesite 18-21.

5. The method for promoting long-term sequestration of organic carbon in sediments according to claim 1, characterized in that: raw material% Serpentine 80 Magnesite 20.

6. The method for promoting long-term sequestration of organic carbon in sediments according to claim 1, characterized in that: The mixed mineral material is spread to a thickness of 1-2 cm on the surface of the sediment.

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